Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/30—Low-molecular-weight compounds
  • C08G18/32—Polyhydroxy compounds; Polyamines; Hydroxyamines
  • C08G18/3203—Polyhydroxy compounds
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/65—Low-molecular-weight compounds having active hydrogen with high-molecular-weight compounds having active hydrogen
  • C08G18/66—Compounds of groups C08G18/42, C08G18/48, or C08G18/52
  • C08G18/6633—Compounds of group C08G18/42
  • C08G18/6637—Compounds of group C08G18/42 with compounds of group C08G18/32 or polyamines of C08G18/38
  • C08G18/664—Compounds of group C08G18/42 with compounds of group C08G18/32 or polyamines of C08G18/38 with compounds of group C08G18/3203
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
  • C08G18/72—Polyisocyanates or polyisothiocyanates
  • C08G18/77—Polyisocyanates or polyisothiocyanates having heteroatoms in addition to the isocyanate or isothiocyanate nitrogen and oxygen or sulfur
  • C08G18/78—Nitrogen
  • C08G18/79—Nitrogen characterised by the polyisocyanates used, these having groups formed by oligomerisation of isocyanates or isothiocyanates
  • C08G18/798—Nitrogen characterised by the polyisocyanates used, these having groups formed by oligomerisation of isocyanates or isothiocyanates containing urethdione groups
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/70—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the isocyanates or isothiocyanates used
  • C08G18/72—Polyisocyanates or polyisothiocyanates
  • C08G18/80—Masked polyisocyanates
  • C08G18/8003—Masked polyisocyanates masked with compounds having at least two groups containing active hydrogen
  • C08G18/8006—Masked polyisocyanates masked with compounds having at least two groups containing active hydrogen with compounds of C08G18/32
  • C08G18/8009—Masked polyisocyanates masked with compounds having at least two groups containing active hydrogen with compounds of C08G18/32 with compounds of C08G18/3203
  • C08G18/8012—Masked polyisocyanates masked with compounds having at least two groups containing active hydrogen with compounds of C08G18/32 with compounds of C08G18/3203 with diols
  • C08G18/8016—Masked aliphatic or cycloaliphatic polyisocyanates
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G2150/00—Compositions for coatings
  • C08G2150/20—Compositions for powder coatings

Definitions

• DE-PS 30 30 572 a process for the production of uretdione group-containing polyadducts and the products produced according to them are presented. These are reaction products from the isocyanurate-free uretdione (UD) of 3-isocyanatomethyl-3.5.5-trimethylcyclohexyl isocyanate (also isophorone diisocyanate or IPDI for short) - which can be prepared according to DE-PS 30 30 513 or DE-PS 37 39 549 - and diols and possibly monoalcohols or amines. The reaction can take place in bulk or in the presence of suitable solvents.
• UD isocyanurate-free uretdione
• IPDI isophorone diisocyanate
• This limit can also be seen in the examples of DE-PS 30 30 572: it is a molecular weight of a maximum of 3,000 or a uretdione / diol molar ratio of 5: 4 with a uretdione quality with a free NCO content of 17 and a total NCO content of 37.8% by weight. If the free NCO content of the isophorone diisocyanate uretdione increases with a constant total NCO content, i.e. H. the degree of oligomerization simultaneously decreases and thus also the molar mass of the uretdione used, the molar mass of the polyaddition products containing uretdione groups accordingly decreases.
• the molecular weights between 550 and 4,300, preferably between 1,500 and 2,000, the uretdione / diol molar ratios are between 2: 1 and 6: 5, preferably 3: 2 and 5: 4 .
• DE-PS 30 30 588 the claimed molecular weights are only slightly changed, namely from 500 to 4,000, preferably 1,450 and 2,800 with a uretdione / diol molar ratio comparable to DE-PS 30 30 539.
• the free NCO content of the crosslinkers had to be taken into account to the extent that the functionality of the hydroxyl-containing polymers has to be matched to the free NCO content in order to avoid gelling during extrusion and thus a loss in quality of the coatings to suppress.
• the OH functionality had to be limited to 2.2 to 3.5, preferably 2.5 to 3.4. Extensive investigations were and still are necessary in order to match resin and hardener.
• uretdione group-containing polyadducts with terminal OH groups are also described and claimed using an example.
• the scope corresponds to the polyaddition product mentioned above.
• the OH-terminated polyaddition products have so far been of no importance for the PU powder coating sector, since the economic value in comparison to the other crosslinking agents was not given; see Example 5 of DE-PS 30 30 572 in comparison to the other examples.
• the numbers speak for themselves.
• the object of the present invention was therefore to find polyaddition products containing hydroxyl and uretdione pen, in order to use these crosslinking agents for the production of PUR powder coatings which are free from cleavage, and the PU powder coatings prepared thereafter which no longer have the disadvantages of the prior art mentioned.
• the present invention accordingly relates to polyaddition products containing hydroxyl and uretdione groups from the uretdione of isophorone diisocyanate and diols and / or chain extenders according to claim 1.
• the invention furthermore relates to the use of the polyaddition products in cleavage-free transparent or pigmented PUR powder coatings of high reactivity and excellent gloss, produced from the blocking agent-free, hydroxyl- and uretdione group-containing, bifunctional polyaddition products and hydroxyl group-containing polymers, as well as the additives customary in PU chemistry.
• the isocyanurate-free uretdione of isophorone diisocyanate is highly viscous at room temperature and greater than 10 6 mpa ⁇ s, at 60 ° C the viscosity is 13 ⁇ 103 mpa ⁇ s and at 80 ° C 1.4 - 103 mpa ⁇ s.
• the free NCO content is between 16.8 and 18.5% by weight, which means that more or less high proportions of polyuretdione of the IPDI must be present in the reaction product.
• the monomer content is - 1%.
• the total NCO content of the reaction product after heating to 180-200 ° C is 37.5-37.8% by weight.
• All diols commonly used in PUR chemistry are suitable for the preparation of the polyaddition products according to the invention containing hydroxyl and uretdione groups, but particularly preferred here are ethylene glycol (E), 1,4-butanediol (B), 1,5-pentanediol, P-1,6-hexanediol ( HD), 3-methylpentanediol-1.5 (Pm), 2.2.4 (2.4.4) -trimethylhexanediol (TMH-d.) And hydroxypivalic acid neopentylglycol ester (Eg).
• inventive polyaddition products advantageously contain chain extenders in the form of linear hydroxyl-containing polyesters with a molecular weight between 250 and 2,000, preferably 300 to 1,500.
• chain extenders in the form of linear hydroxyl-containing polyesters with a molecular weight between 250 and 2,000, preferably 300 to 1,500.
• Diols also used 2-methylpropanediol, 2,2-dimethylpropanediol (NPG), diethylene glycol, dodecanediol-1.1 (Ci2) and trans- and cis-cyclohexanedimethanol (CHDM).
• the preferred dicarboxylic acids include aliphatic, optionally alkyl-branched, such as succinic, adipic (As), cork, azelaic and sebacic acid (Sb), 2.2.4 (2.4.4) trimethyl adipic acid; Lactones and hydroxycarboxylic acids such as E- caprolactone and hydroxycaproic acid are also included.
• inventive diol / chain extender mixtures are used in a ratio of 5:95 to 90:10.
• inventive products can be produced both in the solvent and in bulk, that is to say solvent-free.
• the polyaddition products according to the invention can u. a. can be obtained by the method described as follows.
• the reaction in solvents is generally carried out at temperatures from 50 to 100 ° C., preferably between 60 and 90 ° C.
• the OH component, diols and / or chain extenders are introduced and the uretdione is added as quickly as possible without the reaction temperature exceeds the above limits.
• the reaction is complete after 30 to 150 minutes.
• the solvent is then removed. Steam screws, film trudder or spray dryer are suitable for this.
• Suitable solvents are benzene, toluene or other aromatic or aliphatic hydrocarbons, ethyl acetate such as ethyl or butyl acetate, also ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone or chlorinated aromatic and aliphatic hydrocarbons as well as any mixtures of these or other inert solvents.
• Another object of the invention is the solvent-free and continuous production of the process products by means of an intensive kneader in a single- or multi-screw extruder, in particular in a twin-screw extruder.
• the solvent-free synthesis requires temperatures clearly> 120 ° C. to 190 ° C. It was surprising that such high temperatures can be used for the uretdione syntheses. These temperatures are already well within the range for uretdiones, so that high free isocyanate contents can result and uncontrolled reaction sequences would be expected. This fact was important for the hydroxyl group-containing uretdione polyaddition product synthesis and it was all the more surprising that it could be realized.
• the short reaction times of ⁇ 5 minutes, preferably ⁇ 3 minutes, in particular ⁇ 2 minutes, have proven advantageous.
• the short-term thermal load is sufficient to mix the reactants homogeneously and to implement them completely or largely. Subsequently is cooled in accordance with the equilibrium setting and, if necessary, sales are completed.
• reaction products are fed to the reaction kneader in separate product streams, it being possible for the starting components to be preheated to 100.degree. C., preferably up to 80.degree. If there are more than two product streams, these can also be added in bundles.
• Diol and / or chain extenders and / or catalysts and / or further conventional paint additives such as leveling agents and / or stabilizers can be combined to form a product stream; likewise those that are inert to isocyanate groups: catalysts and corresponding paint additives mentioned above.
• the order of the product streams can also be handled variably and the entry point for the product streams can be different.
• the catalysts customary in PUR chemistry can also be used to accelerate the polyaddition reaction. They are used in a concentration of 0.01 to 1% by weight, preferably 0.03 to 0.5% by weight, based on the reaction components used. Tin II and IV compounds have so far proven to be particularly suitable. Dibutyltin dilaurate (DBTL) is particularly mentioned here. However, other catalysts should not be considered unsuitable from the outset.
• DBTL Dibutyltin dilaurate
• Another object of the present invention is the use of the polyuretdione addition products containing hydroxyl and uretdione groups according to the invention in PU powder coatings, which are surprisingly distinguished by increased reactivity.
• the curing conditions were surprisingly reduced compared to the previously known, which is both economically and ecologically significant.
• Another object of the present invention are cleavage-free polyurethane powder coatings consisting of the polyaddition products according to the invention in combination with polymers containing hydroxyl groups.
• reaction partners for PU powder coatings compounds are suitable which carry functional groups which react with isocyanate groups during the curing process as a function of the temperature and time, e.g. B. hydroxyl, carboxyl, mercapto, amino, urethane, (thio) urea groups.
• Polymers, polycondensates and polyaddition compounds can be used as polymers.
• Preferred components are primarily polyethers, polythioethers, polyacetals, polyesteramides, epoxy resins with hydroxyl groups in the molecule, aminoplasts and their modification products with polyfunctional alcohols, polyazomethines, polyurethanes, polysulfonamides, melamine derivatives, cellulose esters and ethers, partially saponified homo- and copolymers of vinyl esters, but especially polyester and acrylic resins.
• Carboxylic acids preferred for the preparation of polyesters can be aliphatic, cycloaliphatic, aromatic and / or heterocyclic in nature and optionally substituted by halogen atoms and / or unsaturated. Examples include: amber, adipine (As), cork, azelaine, sebacin, phthalic, terephthalic (Ts), isophthalic (Is), trimellitic, pyromellitic, tetrahydrophthalic, hexahydrophthalic, Hexahydroterephthalic, di- and tetrachlorophthalic, endomethylene tetrahydrophthalic, glutaric, maleic and fumaric acid or - if available - their anhydrides, dimethyl terephthalate (DMT), terephthalic acid bis-glycol ester, further cyclic monocarboxylic acid such as benzoic acid, p-tert. Butylbenzoic acid or hexahydro
• polyhydric alcohols such as polyhydric alcohols such.
• B ethylene glycol, propylene glycol-1.2 and -1.3, butylene glycol-1.4 and -2.3, di-ß-hydroxyethylbutanediol, hexanediol-1.6, octanediol-1.8, neopentylglycol, cyclohexanediol, bis- (1.4-hydroxymethyl) cyclohexane, 2.2-bis- (4-hydroxycyclohexyl) propane, 2,2-bis- [4- ( ⁇ -hydroxyethoxy) phenyl] propane, 2-methyl-propanediol-1,3, 3-methylpentanediol-1.5, 2.2.4 (2.4.4) -trimethylhexanediol -1.6, glycerol, trimethylolpropane, trimethylolethane, hexanetriol-1.2.6, butanetriol-1.2.4, tri
• lactones e.g. B. E -caprolactone or hydroxycarboxylic acids, e.g. B. hydroxypivalic acid, Q-hydroxydecanoic acid, Q-hydroxycaproic acid, thioglycolic acid can be used.
• Polyester of silica polyester of phosphoric acid, e.g. B. from Methane, ethane, ß-chloroethane, benzene or styrene phosphoric acid, phosphoric acid chloride or phosphoric acid esters and polyalcohols or polyphenols of the type mentioned above; Polyester of boric acid; Polysiloxanes such as e.g. B. the products obtained by hydrolysis of dialkyldichlorosilanes with water and subsequent treatment with polyalcohols by the addition of polysiloxane dihydrides to olefins such as alkyl alcohol or acrylic acid.
• Preferred polyesters are e.g. B. also the reaction products of polycarboxylic acids and glycidyl compounds such as z. B. are described in DE-PS 24 10 513.
• the particularly preferred hydroxyl-containing polyesters have an OH functionality of> 2, an OH number of 20 to 200 mg KOH / g, preferably 30 to 150 mg KOH / g, a viscosity of ⁇ 60,000 mpa ⁇ s, preferably ⁇ 40,000 mpa ⁇ s at 140 ° C and a melting point of> 70 ° C to 120 ° C, preferably from 75 ° C to 100 ° C.
• glycidyl compounds that can be used are esters of 2,3-epoxy-1-propanol with monobasic acids that have 4 to 18 carbon atoms, such as glycidyl palmitate, glycidyl laurate and glycidyl stearate, alkylene oxides with 4 to 18 carbon atoms, such as butylene oxide and glycidyl ether, such as Octyl glycidyl ether.
• the polyesters can be obtained in a manner known per se by condensation in an inert gas atmosphere at temperatures of 100 to 260 ° C., preferably 130 to 220 ° C., in the melt or in an azeotropic procedure, as described, for. B. in methods of organic chemistry (Houben-Weyl), Vol. 14/2, 1 - 5, 21 23, 40 44, Georg Thieme Verlag, Stuttgart, 1963 or at CR Martens, Alkyd Resins, 51 - 59, Reinhold Plastics Appl. Series, Reinhold Publishing Comp., New York, 1961.
• Preferred acrylate resins which can be used as OH component are homopolymers or copolymers, z.
• the following monomers can be selected as starting products: esters of acrylic acid and methacrylic acid with dihydric, saturated, aliphatic alcohols with 2 to 4 carbon atoms, such as.
• the acrylate resins can be prepared by the customary methods, that is to say by solution, suspension, emulsion or precipitation polymerization; but preferably by substance polymerization, which in turn can be initiated by means of UV light.
• the usual peroxides or azo compounds such as. B. dibenzoyl peroxide, tert-butyl perbenzoate or azodiisobutyronitrile used.
• the molecular weight can e.g. B. with sulfur compounds, such as tert-dodecyl mercaptan, regulated.
• Preferred polyethers can e.g. B. by polyaddition of epoxides such as ethylene oxide, propylene oxide, butylene oxide, trimethylene oxide, 3,3-bis (chloromethyl) oxacyclobutane, tetrahydrofuran, styrene oxide, the bis (2.5) epoxypropyl ether of diphenylolpropane or epichlorohydrin with itself, e.g. B. in the presence of BF 3 , or by addition of these epoxides, optionally in a mixture or in succession, to starting components with reactive hydrogen atoms, such as alcohols or amines, for. B.
• epoxides such as ethylene oxide, propylene oxide, butylene oxide, trimethylene oxide, 3,3-bis (chloromethyl) oxacyclobutane, tetrahydrofuran, styrene oxide
• polyurethanes and / or polyureas containing hydroxyl groups can be used.
• Mixtures of several substances can of course also be used as polymers containing hydroxyl groups.
• the mixing ratio of the hydroxyl-containing polymers and the hydroxyl- and uretdione-containing polyadducts (crosslinking agents) is generally chosen so that 0.5-1.2, preferably 0.8-1.1, very particularly preferably 1, to an OH group 0 NCO group is coming.
• the isocyanate component is used for the production of PU powder coatings with the suitable hydroxyl-containing polymer and, if appropriate, catalysts and pigments and conventional auxiliaries, such as fillers and leveling agents, for.
• suitable hydroxyl-containing polymer and, if appropriate, catalysts and pigments and conventional auxiliaries, such as fillers and leveling agents, for.
• suitable auxiliaries such as fillers and leveling agents, for.
• silicone oil acrylic resins, mixed and homogenized in the melt. This can be done in suitable units, such as. B. heatable kneaders, but preferably by extrusion, temperature limits of 130 to 140 ° C should not be exceeded. After cooling to room temperature and after suitable comminution, the extruded mass is ground to form the ready-to-spray powder.
• the application of the ready-to-spray powder to suitable substrates can be carried out by the known methods, such as. B.
• the coated workpieces are cured for 60 to 4 minutes at a temperature of 150 to 220 ° C, preferably 30 to 6 minutes at 160 to 200 ° C.
• the starting components - cf. Table 1 - are placed in a reactor and heated to - 140 ° C using an oil bath. After most of the substances have melted, 0.1% by weight of di-n-butyltin oxide is added as a catalyst. The first dehydration occurs at 150 to 160 ° C. Within 2 to 3 hours, the temperature is raised to 180 ° C to 190 ° C and the esterification is completed for a further 8 to 10 hours. The bottom product is stirred throughout the reaction time and a gentle stream of nitrogen is passed through the reaction mixture. The acid number of the polyester was always ⁇ 2 mg KOH / g.
• the polyol component - cf. Table 2 - and the catalyst (0.03 - 0.5 wt .-% DBTL), dissolved in the solvent, are placed in the reactor. With vigorous stirring and an inert gas atmosphere, the calculated amount of IPDI uretdione, dissolved in the solvent, is added so quickly that the reaction temperature is 100.degree does not exceed. The reaction is checked by titrimetric NCO determination and is complete after 1 to 3 hours. The solvent is then removed, the product is cooled and, if necessary, crushed. A 2.2 solvent-free
• the IPDI uretdione was fed into the feed housing of a twin-screw extruder at a temperature of 60 to 110 ° C., while the polyol component - cf. Table 2 - was metered in at a temperature of 25 to 110 ° C.
• the uretdione or the polyol component optionally contained the required amount of catalyst - 0.03 to 0.5% by weight of DBTL - based on the end product.
• the extruder used consists of ten casings, five of which are heating zones.
• the temperatures of the heating zones are subject to a wide range - between 50 and 180 ° C - and can be controlled individually. All temperatures are target temperatures, the regulation in the housings is done by electrical heating and pneumatic cooling.
• the nozzle element is heated by an oil thermostat.
• the speed of the twin screw, built up with conveyor elements, was between 50 and 380 rpm.
• the reaction product which accumulates from 10 to 130 kg / h, is either cooled, then crushed or formed and bagged, or the melt is already formed, cooled and bagged.
• the comminuted products, crosslinking agent, polyester, leveling agent, possibly catalyst masterbatch, are mixed intimately with the white pigment, if necessary, in a pan mill and then homogenized in the extruder up to a maximum of 130 ° C. After cooling, the extrudate is broken and with a
• the powder produced in this way is applied with an electrostatic powder spraying system at 60 KV to degreased, possibly pretreated iron sheets and baked in a convection oven at temperatures between 160 and 200 ° C.
• leveling agent - a commercially available copolymer of butyl acrylate and 2-ethylhexyl acrylate - is homogenized in the melt in the corresponding polyester and comminuted after solidification.

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• Chemical & Material Sciences (AREA)
• Health & Medical Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Medicinal Chemistry (AREA)
• Polymers & Plastics (AREA)
• Organic Chemistry (AREA)
• Polyurethanes Or Polyureas (AREA)
• Paints Or Removers (AREA)
• Macromolecular Compounds Obtained By Forming Nitrogen-Containing Linkages In General (AREA)

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• 1994
  • 1994-02-28 DE DE4406444A patent/DE4406444A1/de not_active Withdrawn
  • 1994-12-29 ES ES94120887T patent/ES2114125T3/es not_active Expired - Lifetime
  • 1994-12-29 EP EP94120887A patent/EP0669353B1/fr not_active Expired - Lifetime
  • 1994-12-29 AT AT94120887T patent/ATE163297T1/de not_active IP Right Cessation
  • 1994-12-29 DE DE59405276T patent/DE59405276D1/de not_active Expired - Fee Related
• 1995
  • 1995-02-24 CA CA002143380A patent/CA2143380A1/fr not_active Abandoned
  • 1995-02-27 CN CN95100821A patent/CN1061359C/zh not_active Expired - Fee Related
  • 1995-02-27 AU AU13496/95A patent/AU690953B2/en not_active Ceased
  • 1995-02-28 JP JP7040635A patent/JPH07258379A/ja active Pending
• 2001
  • 2001-11-27 US US09/993,524 patent/US6613861B2/en not_active Expired - Fee Related
• 2003
  • 2003-05-13 US US10/436,044 patent/US6916897B2/en not_active Expired - Fee Related
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